1. Field of the Invention
The present invention relates to a current supply circuit, for example, to be used for supplying a current for generating a supply voltage.
2. Background Art
A current supply circuit for supplying a large current includes, for example, a kicker controller including an operational amplifier of a feedback system and a subsequent current amplifier which is a transistor, and a kicker configured to output a current. In such a circuit, when a high voltage is inputted to a drain side of the current amplifier, an output of the operational amplifier becomes a low voltage. Then, when a low voltage is inputted to the drain side of the current amplifier, it takes a long time until the output of the operational amplifier becomes stable. Accordingly, a required time until an operation of the entire circuit becomes long, resulting in a problem of an inferior responsiveness of the current supply circuit. Further, there has been a problem that a current to be obtained is shifted from a desired value in corner conditions.
Further, as another example of the current supply circuit for supplying a large current, there has been a current supply circuit using a voltage supply. In such a circuit, power consumption tends to be decreased compared to the above mentioned current supply circuit. However, a required time until a voltage of the voltage supply is controlled to be a desired value is long, resulting in an inferior responsibility. Further, in such a case as well, there has been a problem that a current to be obtained is shifted from a desired value in corner conditions.
Further, in the current supply circuit including the kicker controller and the kicker, there has been a problem that a current flowing through a transistor of the kicker controller side cannot be mirrored correctly to a current flowing through a transistor of the kicker side in some cases when a large current is controlled. This problem becomes remarkable particularly when the inputted voltage at the drain side of the current amplifier becomes high, so that a sufficient current necessary for a circuit operation cannot be supplied. In order to solve such problems, a degree of flexibility to control a current and a voltage in the circuit is required to appropriately set the current flowing through the transistor of the kicker side.
A document “Behzad Razavi, “Design of Analog CMOS integrated Circuits”, Original edition copyright 2001 by The McGraw-Hill Companies, Inc.” is an example of the related art of the present application.